docs: add a more complex example.

examples.md

@@ -53,3 +53,47 @@
         (t (string= (car (getitems parent "Name")) "Seeed"))))
 
   ```
+
+- `Artists`: A playlist including everything from a list of artists.
+  ```
+  Id: Artists
+  Name: Artists
+  Program: >-
+    (begin
+      (define *include-artists* '(
+        "seeed"
+        "juli"
+        "falco"
+        "peter fox"
+        "alligatoah"
+        "kraftklub"
+        "wanda"
+        "annennaykantereit"
+        "feine sahne fischfilet"
+        "madsen"
+        "wiener blond"
+        "die toten hosen"
+        "die ärzte"
+        "wir sind helden"
+      ))
+      (define my-prefilter-only-tracks
+        (lambda nil
+          (and
+            (is-type "Audio")
+            (not (name-contains "live"))
+            (not (name-contains "acoustic"))
+            (not (name-contains "instrumental"))
+            (not (name-contains "remix")))))
+      (and
+        (my-prefilter-only-tracks)
+        (is-favourite)
+        (any
+          (lambda
+            (i)
+            ;; the `(and (find-artist)` is here to prevent null violations.
+            (and (find-artist) (string= i (lower (get-name (find-artist))))))
+          *include-artists*)))
+  SortProgram: (begin (shuf *items*))
+  Filename: /config/data/smartplaylists/German.yaml
+  Enabled: true
+  ```